THE PERFORMANCE OF MASONRY  BUILDINGS IN THE 2010/2011      EARTHQUAKE SWARM          Jason Ingham         University of A...
The performance of masonry buildings in      the Christchurch earthquake                Jason Ingham          The Universi...
ContributorsDmytro Dizhur        Lisa Moon            Charlotte Knox    Hossein Derekhshan       Najif Ismail Auckland, NZ...
History of masonryconstruction in New Zealand
Early Construction Practice        Before 1830                         1833              1860       1880
Early Christchurch    Both stone and clay brick masonryVictorian Christchurch in 1885 (Coxhead 1885)   Christchurch’s firs...
1931 Hawke’s Bay earthquake  (256 deaths, 525 aftershocks in 14 days, M7.8)Hastings Street, Napier, circa 1914 (Alexander ...
1931 Hawke’s Bay earthquake                  (earthquake followed by fire)Looking over Napier at the buildings ruined by  ...
Slow steady loss of heritage unreinforced          masonry buildings, post-1930Alexander Turnbull Library           Alexan...
Concrete Masonry Construction flourishes,              1960-1990           1965 Warren Townhouse
1975 Dawn of Capacity Design• Ductility• Confinement• Plastic hinges
Concrete masonry construction today
Clay brick masonry veneer on timber   frame, residential construction
Number of earthquake prone URMbuildings in different regions of NZ    Estimated %NBS of URM buildings in Provinces through...
Tectonic setting
New Zealand’s tectonic setting              Japan                                      California               Taiwan    ...
No known faults
4 September 2010
Earthquake statistics• Date: 04.09.2010 4:35 am (NZ Standard  time)• Magnitude: Mw 7.1• Focal depth: 10 km• Maximum Intens...
Fault trace• Numerous places where offset could be  measured – right lateral up to about 3 m,  with variable vertical thro...
Out-of-plane URM wall failure       162 URM buildings > 10% damage
Parapet failures
22 February 2011
22 February 2011• David Biggs overnighted in Grand Chancellor  hotel• Jason flew from Nelson arriving 7.30 am, bags  check...
22 February, 1pm. M6.3
Sept & Oct 2010Earthquake Swarm                   Nov & Dec 2010                   Jan & Feb (15th) 2011                  ...
Evacuating the city centre (arrived in Chch at 7.30 am, scheduled to depart at 7.30 pm)
Comparison
ComparisonsYear   Event            Country   Magnitude   Duration   Depth   Time    Deaths                                ...
Transect
Command centre   Day 5       Cathedral                 Day 4                         During earthquake
Transect• Designed to sample on a pre-determined  route• Used for sampling biological species• Deficiencies  – Dependent o...
URM = 52%Of URM, 48% redRed URM = 24.8%Some buildings worsethan appear from streetfrontSay about 1 in 3 redoverallThanks t...
Benefits• Immediately of interest to Christchurch City  Council• Requested by the Historic Places Trust• Used to provide a...
Inspections and indicator        buildings
Indicator buildings• If these buildings exhibit damage then others  of this class need to be inspected also• URM: Soft eno...
Concrete buildings
Building Performance (final death toll 181)                                         The Press,                            ...
CanterburyTelevision Building    Following 2010 event,       engineer’s report   recommended repair ofsuperficial damage b...
CTV building
Pyne Gould Corporation Building                     (1963-1964)PGC after 2010 event; before 2011 event   PGC after 2011 ev...
PGC Building
David was one of the last paying customers!                                Grand Chancellor Hotel                         ...
RC Structural Wall Buildings                                  Overall differential settlement of                          ...
Clay brick masonry
Area surveyed
Other locations being inspected                       1000+ clay brick masonry                       500+ concrete masonry...
Is this what we should expect for    an earthquake this intense?                                 (1:10,000 years or 1:3.65...
Is this what we should expect?• Yes. URM buildings consistently collapse in  large earthquakes• The NZ URM building stock ...
Short duration of ground shaking(Less than 10 seconds of string ground shaking on both occasions)                  0.30Acc...
Duration of shaking
Implications for elsewhere in NZ?• The URM building stock throughout NZ is  remarkably homogeneous• The same outcome can b...
Von Sierakowski and Co. Building[1906]                                         [2010]The Von Sierakowski Building, Corner ...
Von Sierakowski and Co. Building[1906]                                         [September 2010]The September Darfield eart...
Von Sierakowski and Co. Building[1906]                                         [February 2011]The September Darfield earth...
The Christchurch Cathedral[1888]                                        [February 2011]The Cathedral was designed by the E...
Poor quality of mortar                       Many tested samples 1.0-1.5 MPaΤ=C+µN                 compression strength
Large vertical accelerations,       short duration                                              Τ=c+µN                    ...
Poor quality of diaphragm timber
Diaphragm Extraction and TestingEstablish the properties of actual heritage diaphragms with true timber species and agedna...
Awnings/canopies and anchorage failures                            Failures observed at both                            en...
Pier failuresDiagonal pier failure reasonably well understoodSpandrel failure over arched windows requires more attention
Spandrel failures
Pounding damageWidespread examples of pounding damage
Pounding damage
Out-of-plane failuresDiaphragm flexibility responsible for failureNote the anchorages into roof diaphragm
Mixed Mode failure(In-plane, Out-of-plane, corner effects)
Multiple events, multiple intensities,multiple directions – fragility functions
Look for cavity construction,No header bricks
Vulnerability of cavity constructionDocumenting damageIdentifying prevalence of failure modesFragility functionsPerformanc...
Performance of seismic       retrofits
Steel strong backs generally performed well
Steel Frames
Shotcrete
Textile Reinforced Mortar
Floor Diaphragm Retrofits
Unsuccessful Parapet Strengthening  Wall has detached from struts
Unsuccessful Parapet Strengthening  (require protection at corners)
Failure of epoxy bonded connections
Churches
Timber frame with masonry veneer      (18)                                 Reinforced concrete                    Timber c...
Damage to rubble masonry        Damage to brick masonry       Damage to a gable in Stconstruction in Holy Trinity    in St...
BasilicaDocumenting damageSystem identificationDamage detectionPerformance in aftershocks
Stone masonry
• Characterisation• Remediation  techniques
Performance of stone masonry         buildings                   Excellent success of horizontal                   and ver...
Success of wall-diaphragm anchorage plates
Reinforced concrete masonry
Reinforced Concrete Masonry Buildings
RCM Cavity construction
Rollerston Courts   Cambridge Courts
Damage to 1 and 2 Story RCM Structures
Damage to 1 and 2 Story RCM Structures              4; 3%   1; 1%                                  None or Non-Visible    ...
Residential, commercial
Conclusions• URM – why was there not more collapses (because of low  duration)?• Massive loss of architectural heritage “C...
As the recovery begins ...• Futility is appearing, public lack of confidence• Insurance companies saying that they will no...
“Is it acceptable that 2 New Zealand cities have been destroyed              by earthquakes in the past 80 years?”        ...
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Prof. Jason Ingham keynote at the North American Masonry Conference, regarding the recent New Zealand earthquakes

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Ingham keynote

  1. 1. THE PERFORMANCE OF MASONRY BUILDINGS IN THE 2010/2011 EARTHQUAKE SWARM Jason Ingham University of Auckland
  2. 2. The performance of masonry buildings in the Christchurch earthquake Jason Ingham The University of Auckland
  3. 3. ContributorsDmytro Dizhur Lisa Moon Charlotte Knox Hossein Derekhshan Najif Ismail Auckland, NZ Adelaide, Australia Auckland, NZ Aurecon, NZ Auckland, NZ Jocelyn Dickie Ilaria Senaldi Jose Centeno Joao Leite Will CyrierCalgary, Canada Pavia, Italy Vancouver, Canada Minho, Portugal Washington State, USA
  4. 4. History of masonryconstruction in New Zealand
  5. 5. Early Construction Practice Before 1830 1833 1860 1880
  6. 6. Early Christchurch Both stone and clay brick masonryVictorian Christchurch in 1885 (Coxhead 1885) Christchurch’s first ‘skyscraper’, photo circa 1910 (Brittenden Collection 1910)
  7. 7. 1931 Hawke’s Bay earthquake (256 deaths, 525 aftershocks in 14 days, M7.8)Hastings Street, Napier, circa 1914 (Alexander View down Hastings Street, Napier after the Turnbull Library). 1931 earthquake (Alexander Turnbull Library).
  8. 8. 1931 Hawke’s Bay earthquake (earthquake followed by fire)Looking over Napier at the buildings ruined by Ruins of the Napier Anglican Cathedralthe 1931 earthquake and the fires (Alexander after the 1931 Napier earthquake Turnbull Library). (Alexander Turnbull Library).
  9. 9. Slow steady loss of heritage unreinforced masonry buildings, post-1930Alexander Turnbull Library Alexander Turnbull Library Wellington, 1950
  10. 10. Concrete Masonry Construction flourishes, 1960-1990 1965 Warren Townhouse
  11. 11. 1975 Dawn of Capacity Design• Ductility• Confinement• Plastic hinges
  12. 12. Concrete masonry construction today
  13. 13. Clay brick masonry veneer on timber frame, residential construction
  14. 14. Number of earthquake prone URMbuildings in different regions of NZ Estimated %NBS of URM buildings in Provinces throughout New Zealand
  15. 15. Tectonic setting
  16. 16. New Zealand’s tectonic setting Japan California Taiwan Chile New Zealand
  17. 17. No known faults
  18. 18. 4 September 2010
  19. 19. Earthquake statistics• Date: 04.09.2010 4:35 am (NZ Standard time)• Magnitude: Mw 7.1• Focal depth: 10 km• Maximum Intensity: MMI 8• No direct fatalities (one heart attack)• 1 major casualty due to falling chimney• Largest earthquake on record to occur within 40 km of major city and cause no fatalities Credit: GeoNet
  20. 20. Fault trace• Numerous places where offset could be measured – right lateral up to about 3 m, with variable vertical throw (mostly < 1 m). Credit: GNS
  21. 21. Out-of-plane URM wall failure 162 URM buildings > 10% damage
  22. 22. Parapet failures
  23. 23. 22 February 2011
  24. 24. 22 February 2011• David Biggs overnighted in Grand Chancellor hotel• Jason flew from Nelson arriving 7.30 am, bags checked on to Wellington• Interviewed by Canterbury TV at 11.00 am• Ken Elwood (Vancouver) in audience• 84 attendees at afternoon seminar• Earthquake struck at 12.51 pm
  25. 25. 22 February, 1pm. M6.3
  26. 26. Sept & Oct 2010Earthquake Swarm Nov & Dec 2010 Jan & Feb (15th) 2011 Feb 22nd – Mar 28, 2011
  27. 27. Evacuating the city centre (arrived in Chch at 7.30 am, scheduled to depart at 7.30 pm)
  28. 28. Comparison
  29. 29. ComparisonsYear Event Country Magnitude Duration Depth Time Deaths (sec) (km)1931 Napier NZ 7.9 150 20 10.47 2561989 Loma Prieta USA 6.9 17 18 17.54 631994 Northridge USA 6.7 15 19 4.31 332001 Nisqualle USA 6.8 10 52 10.54 02007 Gisborne NZ 6.8 7 44 20.55 02009 L’Aquila Italy 6.3 10 10 3.32 3082010 Port-au-Prince Haiti 7.0 35 13 16.53 316,0002010 Maule Chile 8.8 180 35 3.34 5622010 Darfield NZ 7.1 10 10 4.35 02011 Christchurch NZ 6.3 7 5 12.51 1812011 Tohoku Japan 9.0 120-180 32 14.46 25,000
  30. 30. Transect
  31. 31. Command centre Day 5 Cathedral Day 4 During earthquake
  32. 32. Transect• Designed to sample on a pre-determined route• Used for sampling biological species• Deficiencies – Dependent on route, and route was intentionally selected to survey large stock of URM buildings – Level 1 sampling, building condition judged exclusively by appearance of street frontage – Data is subjective
  33. 33. URM = 52%Of URM, 48% redRed URM = 24.8%Some buildings worsethan appear from streetfrontSay about 1 in 3 redoverallThanks to Quincy Ma,Liam Wotherspoon,Rick Henry
  34. 34. Benefits• Immediately of interest to Christchurch City Council• Requested by the Historic Places Trust• Used to provide accurate information to media• Used in response to a request to identify a suite of ‘indicator buildings’
  35. 35. Inspections and indicator buildings
  36. 36. Indicator buildings• If these buildings exhibit damage then others of this class need to be inspected also• URM: Soft enough (damaged) so that it did not take shock of comparable intensity to cause further damage• Other forms: Exhibiting measurable damage that can be easily monitored
  37. 37. Concrete buildings
  38. 38. Building Performance (final death toll 181) The Press, 12/03/2011
  39. 39. CanterburyTelevision Building Following 2010 event, engineer’s report recommended repair ofsuperficial damage but declared building safe.
  40. 40. CTV building
  41. 41. Pyne Gould Corporation Building (1963-1964)PGC after 2010 event; before 2011 event PGC after 2011 event (Brian Neller) (Weng Y Kam)
  42. 42. PGC Building
  43. 43. David was one of the last paying customers! Grand Chancellor Hotel • 1980s construction • Constructed in 2 stages • Core wall up to 7th storey • Perimeter moment frame above • South face dropped 600mm to 900mm due to failure of wall at ground level and columns at 7th storey
  44. 44. RC Structural Wall Buildings Overall differential settlement of around 300 mmLightly confined boundary zones
  45. 45. Clay brick masonry
  46. 46. Area surveyed
  47. 47. Other locations being inspected 1000+ clay brick masonry 500+ concrete masonry 100+ stone masonry 250+ churches Perhaps 25% of all heritage masonry buildings in New Zealand
  48. 48. Is this what we should expect for an earthquake this intense? (1:10,000 years or 1:3.65 million days!) CENTRAL CITY AND NZS1170 SPECTRA CLASS D DEEP OR SOFT SOIL Larger Horizontal Components 1.8 1.6 NZS1170 2500-yr Class D 1.4Demand 1.2 NZS1170 500-yr Class D Deep or Soft Soil CHHC_MaxH_FEB 1 SA(T) (g) 0.8 CCCC_MaxH_FEB 0.6 CBGS_MaxH_FEB 0.4Capacity REHS_MaxH_FEB 0.2 GM_Larger_FEB 0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 Period T(s)
  49. 49. Is this what we should expect?• Yes. URM buildings consistently collapse in large earthquakes• The NZ URM building stock is analogous to that of other European colonies. Past failures elsewhere have relevance to NZ• Unretrofitted URM buildings loaded to about 6 times their calculated capacity• Why did they not all completely collapse?
  50. 50. Short duration of ground shaking(Less than 10 seconds of string ground shaking on both occasions) 0.30Acceleration(g) N64E 0.15 0 -0.15 4 Sept 2010 -0.30 0 10 20 30 40 50 60 Time(s) 22 Feb 2011
  51. 51. Duration of shaking
  52. 52. Implications for elsewhere in NZ?• The URM building stock throughout NZ is remarkably homogeneous• The same outcome can be expected anywhere in NZ after a large earthquake1. Do nothing2. Seismic improvement3. Demolition
  53. 53. Von Sierakowski and Co. Building[1906] [2010]The Von Sierakowski Building, Corner Tuam and Columbo Street (1906). The factorywas erected in 1906 and was the largest wireworks factory in the Colonies.
  54. 54. Von Sierakowski and Co. Building[1906] [September 2010]The September Darfield earthquake of 2010 caused out-of-plane wall failure and lossof the parapet.
  55. 55. Von Sierakowski and Co. Building[1906] [February 2011]The September Darfield earthquake of 2010 caused out-of-plane wall failure and lossof the parapet.
  56. 56. The Christchurch Cathedral[1888] [February 2011]The Cathedral was designed by the Englishman G.G. Scott and work began on it in1863. The tower and spire, paid for by the Rhodes family, are complete in thephotograph but were damaged multiple times by earthquakes in 1881, 1888 whichbrought down part of the top section, and again in 1901.
  57. 57. Poor quality of mortar Many tested samples 1.0-1.5 MPaΤ=C+µN compression strength
  58. 58. Large vertical accelerations, short duration Τ=c+µN If c = 0 and N=0? Vertical accelerations high frequency
  59. 59. Poor quality of diaphragm timber
  60. 60. Diaphragm Extraction and TestingEstablish the properties of actual heritage diaphragms with true timber species and agednail connections. Test both roof and floor diaphragms
  61. 61. Awnings/canopies and anchorage failures Failures observed at both ends of braces
  62. 62. Pier failuresDiagonal pier failure reasonably well understoodSpandrel failure over arched windows requires more attention
  63. 63. Spandrel failures
  64. 64. Pounding damageWidespread examples of pounding damage
  65. 65. Pounding damage
  66. 66. Out-of-plane failuresDiaphragm flexibility responsible for failureNote the anchorages into roof diaphragm
  67. 67. Mixed Mode failure(In-plane, Out-of-plane, corner effects)
  68. 68. Multiple events, multiple intensities,multiple directions – fragility functions
  69. 69. Look for cavity construction,No header bricks
  70. 70. Vulnerability of cavity constructionDocumenting damageIdentifying prevalence of failure modesFragility functionsPerformance of retrofit technologiesRepair vs demolish scenarios
  71. 71. Performance of seismic retrofits
  72. 72. Steel strong backs generally performed well
  73. 73. Steel Frames
  74. 74. Shotcrete
  75. 75. Textile Reinforced Mortar
  76. 76. Floor Diaphragm Retrofits
  77. 77. Unsuccessful Parapet Strengthening Wall has detached from struts
  78. 78. Unsuccessful Parapet Strengthening (require protection at corners)
  79. 79. Failure of epoxy bonded connections
  80. 80. Churches
  81. 81. Timber frame with masonry veneer (18) Reinforced concrete Timber construction or steel structure (16) (20) URM stone (22) URM brick Approximately 250 (24) churches
  82. 82. Damage to rubble masonry Damage to brick masonry Damage to a gable in Stconstruction in Holy Trinity in St Luke’s church (1859), James church (1926),church (1872), Avonside Christchurch Riccarton Plaster Brick Unrein. (?) concrete Stone 10 220 170 230 St James Church (1926), Riccarton; wall composition
  83. 83. BasilicaDocumenting damageSystem identificationDamage detectionPerformance in aftershocks
  84. 84. Stone masonry
  85. 85. • Characterisation• Remediation techniques
  86. 86. Performance of stone masonry buildings Excellent success of horizontal and vertical post-tensioning
  87. 87. Success of wall-diaphragm anchorage plates
  88. 88. Reinforced concrete masonry
  89. 89. Reinforced Concrete Masonry Buildings
  90. 90. RCM Cavity construction
  91. 91. Rollerston Courts Cambridge Courts
  92. 92. Damage to 1 and 2 Story RCM Structures
  93. 93. Damage to 1 and 2 Story RCM Structures 4; 3% 1; 1% None or Non-Visible Minor 61; 47% Severe 63; 49% Failure
  94. 94. Residential, commercial
  95. 95. Conclusions• URM – why was there not more collapses (because of low duration)?• Massive loss of architectural heritage “Christchurch now has no earthquake-prone buildings”• Clear lesson for all of NZ regarding earthquake prone buildings. Improve or remove• Better knowledge of URM and diaphragm materials• Proven success of a number of retrofit technologies• Good data on seismic performance macros URM building stock and of churches• RCM failures mostly attributable to poor grouting and rebar detailing
  96. 96. As the recovery begins ...• Futility is appearing, public lack of confidence• Insurance companies saying that they will not insure a strengthened URM building• Used to be 1/3rd of 0.22. Now 2/3rd of 0.30 (strengthening requirement is now 3 times what it was a year ago)• “Knock them all down – its too hard to make them safe”
  97. 97. “Is it acceptable that 2 New Zealand cities have been destroyed by earthquakes in the past 80 years?” Nigel Priestley at the PCEE conference

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